Machine for forming random fiber webs

ABSTRACT

The atomization chamber or air duct between the lickerin and the condenser of a machine for forming random fiber webs is provided with a floor of airfoil shape and the duct cover or roof is inclined to the floor at an angle of not more than 15*. The doffing bar is here formed integral with the roof or cover, and is rounded at the entrance end of the duct. The saber is spaced from the entrance end of the floor to allow air flow under as well as over the saber; and an adjustable damper or valve is provided to control the amount of air flow under the saber.

United States Patent 1 Wood 7 Oct. 30, 1973 241,001 12/1959 Australia 19/156 Primary Examiner-Dorsey Newton Attorney-Shlesinger, Fitzsimmons & Shlesinger [57] ABSTRACT The atomization chamber or air duct between the lickerin and the condenser of a machine for forming random fiber webs is provided with a floor of airfoil shape and the duct cover or roof is inclined to the floor at an angle of not more than 15. The doffing bar is here 3 formed integral with the roof or cover, and is rounded MACll-IINE FOR FORMING RANDOM FIBER WEBS [75] Inventor: Dennis E. Wood, Penfield, NY. [73] Assignee: Curlator Corporation, East Rochester, NY.

[22] Filed: Dec. 31, 1970 [21] Appl. No.: 103,104

[52] US. Cl. l9/I56.3, 19/89 51 1nt.Cl. ....-D0i 25/00 [58] Field of Search 19/155, 156-1564, 19/205, 88, 89; 156/622, 369-377 56 References Cited UNITED STATES PATENTS 2,876,500 3/1969 Buresch et al. 19/205 X 2,700,188 l/1955 Buresch et al. 19/89 X 2,703,441 3/1955 Langdon et a1 19/89 X 3,535,187 10/1970 Wood .1. 156/372 x 2,071,438 2/1937 Shorter et a1. [9/89 FOREIGN PATENTS OR APPLICATIONS 562,308 6/1944 Great Britain 19/205 at the entrance end of the duct. The saber is spaced from the entrance end of the floor to allow air flow under as well as over the saber; and an adjustable damper or valve is provided to control the amount of air flow under the saber.

3 Claims, 3 Drawing Figures PATENH-Iflnm 30 ms INVENTOR. DENNIS E. WOOD ATTORNEYS Y PATENTEUnmnms 3.768119 SHEET 3 [1F 3 K! m INVENTOR. DENNIS E. WOOD 1 BY MZL ATTORNEYS MACHINE FOR FORMING RANDOM FIBER WEBS The present invention relates to machines for formin g random fiber webs, and constitutes an improvement in certain features over the machine disclosed in the Langdon et al. US. Pat. No. 2,890,497, issued June 16, 1959.

In the following description, parts which are identical, or substantially identical with .parts disclosed in U.S. Pat. No. 2,890,497 are designated by the same reference numerals as in that patent; and reference can be had to that patent for a more detailed description of the construction, function, and operation of those parts.

In the machine of US. Pat. No. 2,890,497, and particularly in the embodiment thereof shown in FIG. of that patent, the floor 362 of the atomization chamber or duct is flat; and a cylindrical doffing bar 292 is used to aid in doffing fibers from thelickerin 155 to deliver them into the duct.

With a machine so constructed, it is difficult to maintain separated distribution of the fibers in the air stream before the fibers are laid down on the condenser 165. The result is that the fibers, which are opened at the nose-bar-feed-roll area 152-130, and which are atomized by the air at the saber 360, may become entangled and coagulated to form small tufts of fibers which are laid down as tufts on the condenser, causing what may be described as a cloudy effect in the appearance of the random fiber web formed in the machine, and hence seriously detracting from the uniformity of the web.

A primary object of this invention is to avoid the defects of the prior construction, and improve the quality of the web formed on. the condenser.

To, this, end, a further purpose of the invention is to greatly improve the air and fiber flow through the chamberthrough which the fibers are carried by the air from the lickerin to the condenser.

, A further object of the invention is to provide a machine in which the'air may travel at an increased velocity through the fiber duct or chamber, without any increase in the amount of air moved between the input duct and the condenser, so that the web has a more uniform appearance and a greaterrandom displacement of the fibers.

Otherobjects of the invention will be apparent here inafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.

In the drawings:

FIG. 1 is a fragmentary vertical sectional view through the webbing portion of one type of random fiber web forming machine built to include the improvements of the present invention;

FIG. 2 is a more or less diagrammatic view on an enlarged scale illustrating the improved duct or chamber construction, the improved doffing bar construction, and the improved position of the. saber; and

FIG. 3 is a fragmentary vertical sectional view erin past a saber tube 360, and are doffed from the lickerin by centrifugal force due to the high speed rotation of the lickerin, and by air flowing from duct 400 past the teeth of the lickerin.

The air is supplied by a fan 355 through the air duct 400, and passes over the saber tube 360 between the lickerin and this tube. However, whereas in conventional construction, the saber tube is disposed at the juncture of one side of the air duct and the floor of the atomization chamber or duct 365 so that all the air must pass over the top of the saber, in the improved construction of the present invention, the saber is separated from the duct wall 403 to provide a by-pass under the saber'for the air; and, in addition, an adjustable flap-valve 405 is provided at the by-pass duct 404 to control the proportion of air passing under the saber. The valve 405 comprises a flexible plate secured to a half round member 407 which is journaled at opposite ends in the sidewalls of the machine.

In the improved machine, the longitudinal cross sec tionof the atomizing chamber or delivery duct 420 is altered. At its entering end, the duct cover 424 is formed with a rounded nose portion 414 that acts as a doffing bar to doff fibers from the lickerin as the lickerin rotates past the doffing bar. This nose portion is bounded by converging upper and lower walls 415, 416 that converge at the rounded end 417.

In addition, the floor 422 of the air duct or atomization chamber 420 has been changed from a simple inclined flat plate to an airfoil surface. This surface is coupled with a duct cover 424 whose lower surface 423 has a flatter profile than conventional such surfaces, and is positioned to provide a much reduced included angle between the opposed floor and cover surfaces of not more than 15.

In this machine, the condenser is an endless -foraminous belt 430 which is shown only fragmentarily in FIG. 1, and which travels over a plurality of guide rollers, two of which are indicated at 431 and432. The fibers carried by the airthrough the duct 420 are depositedon thetravelling foraminous belt 430; and the air passes through the belt and returns to the fan 355 which delivers it again into the duct 400.

v The atomization chamber of the machine described is of rectangular cross-section. It has parallel side walls and top and bottom walls inclined to one another at the optimum angle of approximately 11. However, with the efficiency of the flow of air and fibrous particles the angle of divergence between the top and bottom walls of the chamber will decrease to a minimum of 6 as the Reynolds number is increased. The Reynolds number is a non-dimensional factor indicating the frictional resistance of the flow. This frictional resistance is due to the frictional drag on the surface; and the physical property governing this resistance is its coefficient of through the webbing portion of another type of random viscosity. To reduce this frictional drag within the atomization chamber, all surface finishes should have a maximum roughness of 'micro-inches.

The viscosity of the fibrous flow increases with an increase of temperature of the flow. The maximum thickness t of the aerofoil duct floor 422 (FIG. 2) as measured from the chord length [should not exceed 14 percent of l, and 2t/l 0.28.

Also the maximum thickness t of the aerofoil should not be more than 0.4 I from the leading edge, e.g., x 0.4 l. The minimum distance ofx at t max. should not be less than 0.15 l.

The new construction has greatly improved the air and fiber flow through the duct or chamber 420, causing the fiber and air to have a much straighter path at an increased velocity without any increase in the amount of air used between the input end of this duct or chamber and the condenser. As a result, the web laid down has a more uniform appearance and a greater random displacement of the fibers in the web.

In the improved construction, moreover, the fibers and air are mixed as previously but due to the increased air flow resulting from the airfoil floor and the duct cover, the fiber maintains the velocity imparted at the saber and is not acted upon by pockets of turbulence, eddies, etc. The angle of between the floor and the cover of this duct significantly reduces the shock to the flow heretofore caused by too rapid expansion of the air and fiber mixture. The small angle of divergence between the floor and the cover of the duct, and the length of the passage are closely linked so that drag and friction looses are reduced, and the passage of the fibers does not reduce the kinetic energy of the flow. Also, since the angle of divergence is a function of the total pressure loss in the divergent sections, the improved chamber has less pressure losses.

Furthermore by including an air by-pass duct under the saber, air can flow across the surface of the airfoil floor under the fiber flow so as to obviate any eddies that might be caused by the boundary layer flow across this surface.

Still further, the improved shape of the doffing bar reduces the turbulence pocket created in a position fronting the round saber bar.

FIG. 3 illustrates an application of the invention to a vertical random web former.

In this machine fibers carried by an air' stream are supplied to the chute 600. The air is sucked by a fan, not shown, through the rotating screen or condenser 603, causing the fibers to be deposited on this screen or condenser which may be of conventional construction. Wipers or seals 605 are mounted on the stationary body portion 607 of thecondenser to engage the inside of the screen as it revolves.

The portion .608 of the feed chute is curved so that it converges with reference to the screen 603 and the fibers are compressed between it and the screen and formed into a mat. A roller 610 doffs the mat from the condenser screen onto the feed plate 630. A rotating feed roller 552 feeds the mat over the nose 551 of the feed plate into the rotating lickerin 555, which combs the fibers from the mat.

The fibers are doffed from the lickerin by centrifugal force due to the high speed rotation of the lickerin and by an air stream flowing in the duct 500 tangentially past the teeth of the lickerin. The air stream in duct 500 is created by the fan 573 which is driven by a motor 612 and which supplies an air stream under pressure to the duct 500 through the duct 574.

As in the first described embodiment of the invention, a flexible flap valve 505, which is pivoted at 507 on the duct wall 614 controls the direction of flow of the air from duct 500 over the saber 560. When this valve is open, the air can flow around the saber to obviate any eddies that might be caused by boundary layer flow across the surface of the airfoil.

This airstream flows into the atomization chamber or duct 520 which, as in the previously described embodiment of the invention, has an airfoil bottom floor 522 and a flat roof 524 which is inclined to the bottom floor at the entering end of the duct or chamber at an angle of 15 or less. The fibers are carried by the airstream onto the condenser 530 which is here an endless foraminous belt passing over two or more rollers 531, one of which is the driver for the belt. A suction box 570 between the upper and lower reaches of the belt causes the fibers to be deposited as a random fiber web on the belt. The suction box is connected through port 571 and duct 572 to the suction side of the fan 573.

While the invention has been described in connection with two specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any modifications or embodiments of the invention that come within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. In a machine for forming random fiber webs having a rotary lickerin a movable foraminous condenser,

a duct extending from the lickerin to the condenser,

means for feeding a fiber mat to the lickerin so that the lickerin in its rotation combs fibers from the mat, and

means for supplying an air stream at the lickerin end of said duct to cause fibers doffed from the lickerin to be conveyed by the air stream to the condenser,

the improvement wherein the floor of said duct is of airfoil shape and is convexly curved to converge toward the roof of the duct from the entering end of the duct to a point intermediate the ends of the duct and then diverges from the roof of the duct to the condenser end thereof,

the point where the floor is closest to the roof of the duct being closer to the lickerin than to the condenser and being adjacent the place of doffing of the fibers from the lickerin,

a removable saber disposed adjacent the entering end of the floor of said duct but spaced therefrom so that air supplied to said duct will flow around both the top and bottom of the saber, and means for adjustably regulating the amount of air passing under the saber. I

2. In a machine for forming random fiber webs having a rotary lickerin,

a movable foraminous condenser,

a duct extending from the lickerin to the condenser,

means for feeding a fiber mat to the lickerin so that the lickerin in its rotation combs fibers from the mat,

means for supplying an air stream at the lickerin end of said duct to cause fibers doffed from the lickerin to be conveyed by the air stream to the condenser,

the improvement wherein the floor of said duct is of airfoil shape,

a removable saber is disposed adjacent the entering end of the floor of said duct but is spaced therefrom so that air supplied to said duct will flow around both the top and bottom of the saber, and

having means for adjusting the amount of air flow under the saber, and

said adjusting means is a valve mounted to pivot adjustably toward and from the saber.

a saber disposed adjacent the junction of said conduit and said duct and confronting the lickerin, said saber being spaced from opposite sides of the conduit and from the floor of said duct whereby the air flowing from said conduit into said duct passes over and under the saber,

and means for adjustably regulating the amount of air passing under the saber,

and said adjusting means comprises a valve pivoted at one end in said conduit and movable toward and away from said saber. 

1. In a machine for forming random fiber webs having a rotary lickerin a movable foraminous condenser, a duct extending from the lickerin to the condenser, means for feeding a fiber mat to the lickerin so that the lickerin in its rotation combs fibers from the mat, and means for supplying an air stream at the lickerin end of said duct to cause fibers doffed from the lickerin to be conveyed by the air stream to the condenser, the improvement wherein the floor of said duct is of airfoil shape and is convexly curved to converge toward the roof of the duct from the entering end of the duct to a point intermediate the ends of the duct and then diverges from the roof of the duct to the condenser end thereof, the point where the floor is closest to the roof of the duct being closer to the lickerin than to the condenser and being adjacent the place of doffing of the fibers from the lickerin, a removable saber disposed adjacent the entering end of the floor of said duct but spaced therefrom so that air supplied to said duct will flow around both the top and bottom of the saber, and means for adjustably regulating the amount of air passing under the saber.
 2. In a machine for forming random fiber webs having a rotary lickerin, a movable foraminous condenser, a duct extending from the lickerin to the condenser, means for feeding a fiber mat to the lickerin so that the lickerin in its rotation combs fibers from the mat, means for supplying an air stream at the lickerin end of said duct to cause fibers doffed from the lickerin to be conveyed by the air stream to the condenser, the improvement wherein the floor of said duct is of airfoil shape, a removable saber is disposed adjacent the entering end of the floor of said duct but is spaced therefrom so that air supplied to said duct will flow around both the top and bottom of the saber, and having means for adjusting the amount of air flow under the saber, and said adjusting means is a valve mounted to pivot adjustably toward and from the saber.
 3. In a machine for forming random fiber webs having a rotary lickerin, a movable foraminous condenser, a duct extending from the lickerin to the condenser, means for feeding a fiber mat to the lickerin so that the lickerin in its rotation combs fibers from the mat, and means including a conduit for supplying air to said duct at the lickerin end of the duct to cause fibers doffed from the lickerin to be conveyed by the air stream to the condenser, the improvement comprising a saber disposed adjacent the junction of said conduit and said duct and confronting the lickerin, said saber being spaced from opposite sides of the conduit and from the floor of said duct whereby the air flowing from said conduit into said duct passes over and under the saber, and means for adjustably regulating the amount of air passing under the saber, and said adjusting means comprises a valve pivoted at one end in said conduit and movable toward and away from said saber. 